Bluetooth Low Energy (BLE) relates to Bluetooth wireless radio technology. It has been designed for low-power and low latency applications for wireless devices within short range. Today, BLE applications can be found from healthcare, fitness, security, smart energy, industrial automation and home entertainment. However, BLE is not limited only those, but increasingly more new application utilizing BLE technology are designed.
The difference between BLE and classic Bluetooth is that the BLE devices consume remarkably less power for communication than classic Bluetooth devices. In addition, the BLE is able to start the data transmission much quicker than the classic Bluetooth. This makes it possible to have BLE devices constantly on and to communicate intermittently with other devices.
In BLE technology, one or more so called slave devices can be connected to a master device. To let the master know about the slave devices before connection, the slave devices (or at that point “advertisers”) periodically, at pseudo-random intervals, pass advertisement packets which the master device (also known as scanner device, i.e. “scanner”) is scanning. Depending on the type of advertisement packet sent by a slave device, the master device may respond to the received advertisement packet by requesting a connection with the slave device, or may respond by requesting further information from the advertising device. Beacons are a particular type of BLE advertiser device that transmit advertisement packets with a unique identifier to nearby portable electronic devices such as smart phones. An application on a portable electronic device may respond to information within an advertisement packet received from a beacon by performing an action, such as approximating the location of the portable device.
FIG. 1 illustrates a conventional link layer 150 configured for operation between a host interface 170 and a radio interface 180 of a BLE module. As shown, link layer 150 includes a scanner/initiator state 160 for scanning and initiating connections, an advertiser state 162 for advertising, and multiple connections 1521-1523. In the operation of conventional link layer 150, non-connected tasks such as advertising can operate in only one state at a time, and can only have one set of advertisement parameters including, for example, advertisement interval, advertisement data, transmit (TX)-power, and device address. Thus, such a conventional BLE module device can only operate in only one mode at time, and if the device is in a non-connectable beacon state it cannot receive connections. When operating as a master device, a BLE module 100 may be simultaneously connected to multiple slave devices by respective multiple connections 1521-1523.